A sorting device of the kind mentioned in the opening paragraph is known from the brochure "Indexing and Sorting of Letter-Mail" issued in November 1985 by Nederlandse Philips Bedrijven B. V., Industrial & Electro-Acoustic Systems, Advanced Automation Systems. The known sorting device, which has the type number PS 1010, is used for automatic sorting of postal items such as letters and comparatively thin postal parcels which carry an address code. The postal items are transported from the input position to an automatic address code reader and are subsequently transported to a selected output position in sequential manner by the transport device, which device comprises an assembly of rollers, conveyor belts and transport ropes, and which forms a single route. The output positions are arranged along a number of side branches of the transport device and are selectively accessible through the use of adjustable switching flaps. The known sorting device is provided with an electronic control unit which controls the switching flaps on the basis of data provided by the address code reader.
A disadvantage of the known sorting device is that the sorting device has a limited transport capacity owing to the sequential transport of the postal items. Comparatively heavy postal items, which are moved through the transport device at a comparatively low speed, can accordingly only be sorted with a comparatively low capacity.